* Fix recursive reference memory leak in UIWidget
* Make Event/ScheduledEvent memory-leak safe
* Fix exit crashs by freeing graphics resources before destroying GL context
* Add many asserts to avoid any leak regression
* fix battle rendering
* fix rendering glitch when following creatures
* properly throw exceptions from C++ to lua and avoid exception crashs
* fixes rendering states in framebuffer
* the rendering now consits of two panes
- the background pane (for animated stuff like the map)
- the foreground pane (for steady stuff, like UI)
each pane has it own max FPS and works idependently
this may increase graphics performance on many platforms
* option to pass -opengl1 or -opengl2 as argument
* note that with this commit there are a lot of graphics regressions and the master will remaing unstable for a while
* shaders disabled for a while
* implement draw clipping using opengl stencil buffers
* allow to create Widgets by style name with g_ui.createWidgetByStyle
* styles can now have children widgets
* make proper use of the isNotPathable in pathfinding
* add scrollbar skin
* zooming without real FBOs kinda works, but with lower quality
* hardware detection for glGenerateMipmaps
* possibility to disable bilinear filtering, mipmaps, framebuffers, and realtime mipmap generation in g_graphics
* otclient works well using 3D acceleration in VirtualBox again
* many fixes regarding FBOs fallback implementation
* use OpenGL 2.0 auxiliary buffers when FBO is not supported, thus this means that OpenGL 3 is not a requirement anymore, so otclient might work in older video cards
* map zooming will never work well with Opengl 2.0 because of glCopyTexSubImage2D limitation
Eduardo Bart